It seems imminently relevant in today's climate of promotion to worksite health programs to determine the outcomes for different expenditures of an employer-sponsored program in bp control. Managers of private industry need to make investment decisions regarding bp control programs; they would like to know for each dollar they invest in bp control the amount of reduction in bp and the subsequent effects of bp reduction (for example, on the number of claims paid, and the specific effects on insurance costs, or employee absenteeism). It is ultimately only managers who can make these decisions, and detailed, specific outcomes and expenditure data are needed by them. The proposed study will address some of the issues relevant to health care costs and benefits from the perspective of management. For a cohort of over 3,000 employees, information will be analyzed from two independent sources (i) Blue Cross insurance claims for the period January 1, 1978 through December 31, 1980 and (ii) questionnaire responses and blood pressure measurements from the Baltimore Worksite Blood Pressure Control Project conducted between July 1978 and December 1980: (1) to compare for normotensives, high normals, and hypertensives (a) the dollar amount and number of claims paid by the insurance carrier for 1978, 1979, and 1980, and (b) the dollar amount and number of each type of claim for each six-month interval in the three-year period; (2) to estimate the dollar amount and number by type of health care insurance claims which can be attributed to hypertension from a determination of the increment in claims incurred by hypertensives relative to those incurred by non-hypertensives (both high normals and hypertensives) over the three-year period; (3) to study the effect of blood pressure change in hypertensives on the dollar amount and number of insurance claims by before and after comparisons (1978 vs 1979 vs 1980).